I use these exact ones to sleep. I put in earplugs, put the headphones on, and put in an audiobook in a language other than English. That was it’s easy to tune out of the story and drift off, but it masks snoring and other night noises, and also helps me get back to sleep easier if I wake up in the night.
If you sought professional help for this, the chances are they would try something like exposure therapy (where you deliberately experience the undesired stimulus in a limited context, in a safe and comfortable environment, and try to learn to tolerate or accept it), or perhaps acceptance therapy, which in practice might be more or less the same, but with more of an emphasis on realising that you are reacting and taking control of that. (Both of those descriptions are vast oversimplifications and I’m sure also there are people for whom this doesn’t work, and other people who probably say it’s all bunk).
These are, in theory, things you could try on your own if you research them properly.
I’ve had some success in dealing with annoying noises (not misphonia, just things like noisy neighbours or incessant leaf blowers) by focusing on the fact that the noise is not me. The noise is external to me and is in contrast to me - I am calm and quiet; the noise is not mine and does not belong to me.
This may sound silly, but have you tried a fidget toy?
This sounds a lot like how ADHD affects some people. Not the reaction (anger), but the inability to properly handle external stimuli. Having something on hand to focus on might help.
But that’s a bit of a WAG. I’ve never heard of this condition before and can only relate it to things I’m familiar with. Therapy is your first and best solution at the moment, and a therapist will be much better equipped to suggest workable coping mechanisms.
This site seems to recommend an approach similar to what @Mangetout alluded to, above:
Have you talked with a local audiologist?
ETA: here’s a published article about a pharmacological approach:
I might guess that people without misophonia could understand your reaction if they think about how they feel from a sound like nails on a chalkboard. For most people, that sound will have them react very strongly to the sound and they may react in a primitive way to get the sound to stop. From your description, it seems like you have that kind of reaction to sounds that most people consider benign or can easily ignore.
I was rather surprised to discover that adding earplugs significantly improved the sound quality.
I assume you know that some people must chew gum to clear their ears while flying. I don’t have that problem, but I know people who do, and it’s painful if they don’t clear their ears. I know that doesn’t help you, but it’s not like they’re doing it to annoy you.
I cannot thank you all enough. I am for sure going to try the sound-cancelling phones, and i need to look into the therapy options… Sometimes, such as when I am performing (music) live, though, it’s not an option.
Seriously, though, much thanks to this community for the answers.
My misophonia is relegated to just cupboard / drawer / door slammers, and tabletop / counter smackers. Distinctly unnerving. Gotten into good, healthy rooommate fights over it.
The humming frequencies from neighbouring apartment roof fans keep me awake at night. It’s like my hearing is too good, despite that 25-year chapter of yelling and drumming in absolutely ear-splitting punk/hc/grind/metal bands (wore ear protection the whole time). Tried every earplug and noise-cancellation machine in existence without any luck - pretty sure the frequencies come up through the bed, pillow, and then through my skull. 
Being able to hear pins drop sucks.
Just an idea, perhaps a direction to pursue with a therapist trained in it (DBT) if working through the book yourself isn’t helpful.
At least at less than $10 you can check it out on your own schedule and see if DBT has something to offer.
DBT has lots of tips and tactics for increasing distress tolerance, which might help you when you want to slap a gum chewer or feel like you have to ditch your cart and run screaming into the parking lot.
But why must they chew with their fucking mouths smacking open and closed like cattle chewing their cud!? I also chew gum when taking off/landing for my ears and opening your mouth is not a necessity.
I do not understand how so many adults have never learned to chew with their mouths closed but like the OP, the sound of that makes me want to stab them in the face.
You could bring a portable chalkboard to a restaurant and start scraping your fingernails across it if staff isn’t interested in doing anything about obnoxious noise.
The other day Mrs. J. and I were seated in a restaurant and I got up to use the restroom after ordering. When I came back Mrs. J. was in the process of being moved to another table. Her explanation was that the customers in the next booth had started singing along to the recorded music playing overhead. The server was sympathetic.
This was 30 years ago and I still have flashbacks. Not often, just during these conversations.
I was at a restaurant and could hear someone eating 30 feet away. I looked over at her and could literally see her uvula while she chomped on her salad.
I’ve helped raise cows with better table manners.
I was surprised I didn’t see her stick her tongue up her nose (a cow thing).
I suffer from it too, eating noises are especially triggering for me. I always eat with other people in noisy places or have the tv on to drown out mouth sounds.
Also, I am on antidepressants for depression and anxiety and that has somewhat helped me.
The notion that one should chew with mouth closed is nothing more than a social convention. There are cultures where nobody cares how much mouth noises you make when eating and (I believe) there are cultures where it is an expected behaviour and a way of signalling pleasure and gratitude to a host.
I mean, I was brought up to eat quietly, and it sometimes bothers me a bit when I hear smacking and slurping, but I think it’s important to recognise there is not a jot of objectivity, nor objective superiority in all of this.
I’m with you except I’d like to add it is a physical thing that originates in the limbic system, and all the reasoning in the world doesn’t make unwanted sounds any more bearable to the sufferer.
My personal sore spot is peoples’ voices / regional accents. When we have discussions here about how there’s no such thing as a neutral accent or a “correct” way to pronounce words, I know it’s true, but that doesn’t make my skin crawl any less.
Fair enough. We can’t always control how we feel, but we can usually control how we behave.
The conscious part of our brains that knows we are not being objective can, I believe, be trained to assert dominance in many cases. There will be exceptions.
The sounds that people make while eating make me crazy. I don’t think that people who don’t have this issue can understand. I have to block my ears, leave the space, or ask the person to stop chewing. I even have a visceral reaction when I hear people eating with their mouths closed. Some people are just so loud chewing that closing their mouth has no effect. I have managed to train myself not to scream or run in most situations, but I am utterly revulsed.
I’m afraid that avoidance and exposure “therapy” are the only things that have worked for me.
I am not a doctor and may, plausibly be just some crank on the internet.
I have a personal, loose theory/understanding that the brain can be separated into two parts - the front and the back. The back is more instinctual, gut logic, emotional sorts of thinking and the frontal part does more of the memory and logical analysis. (And yes, I’m sure that the physical split out of this description is probably not valid once you get into the nitty-gritty but the physical layout is not the most important part of the theory.)
In that model, if you’re living a good, healthy and nutritious life then your body spends the extra energy to build out the front part of the brain and those are more capable of suppressing the messages from the back. This is like how your body handles food for maintaining the organs versus growing muscle and fat. If you’re on subsistence, then it just puts everything towards keeping the basic organs going. Once you have more than that, it starts building out muscles and fat, to allow more advanced operations.
Our brain is sectioned similarly. Instinct is what got us through millions of years of evolution. Rationality, great as it may be, just doesn’t have the proven capabilities of animal instinct. If ever there’s a mass extinction event and we all have to start surviving in caves and climbing trees, that’s the part that we want to ensure we keep.
If you’re underweight and poorly nourished, then you’re going to be more susceptible to phobias, chemical imbalances, and instinctual nonsense. If you’re well nourished, the front part of the brain will develop and it will do a better job of suppressing all of that.
And similar to how you might choose to build muscle rather than fat, when you’re well nourished, through a mixture of targeting your nutrition (increasing protein consumption and setting fat consumption to a hard limit) and exercise, you might be able to do the same with the brain. It’s plausible that fish oil, tiny amounts of dietary lithium, and periodic citicoline might help on the nutrient side (daily citicoline seems to lead to tolerance so I doubt its ability to boost development if used in that way). On the exercise side, doing what the others suggest for training your brain to accept it and move on, would probably be good.